This invention relates to a high efficiency furnace and, in particular to an inducer fan unit for use in a high efficiency multi-poised gas furnace.
In general, gas furnaces that are used to heat homes or small buildings draw air from the comfort region being serviced, heat the air within a heat exchanger, and return the heated air back to the comfort air region. The heat exchanger typically contains a series of passages, each of which is heated by an ignited air/gas mixture and the products of combustion are vented by a flue pipe to the surrounding ambient. Air drawn from the comfort region is arranged to pass over the exterior surfaces of the heat exchanger where it is heated prior to being returned to the comfort region.
The flue gas leaving the heat exchanger is delivered into a collector box from which it is discharged to ambient via a chimney or flue pipe. An inducer fan is typically located in the collector box which induces sufficient draft in the flue gas flow to optimize combustion within the furnace.
Many later model gas furnaces are arranged so that they can be mounted and operate efficiently in a number of different positions. These furnaces are referred to as multi-poised units. Generally, the furnace is in an up-flow position wherein the unit is in a normal upright position and room air moves from a bottom entrance upward through the heat exchanger into return air duct located in the top of the unit. The unit can also operate in an inverted position wherein room air flows in the downward direction. In addition, the furnace may be positioned on its side whereupon room air can flow through the furnace generally in horizontal direction to either the right or left side of the furnace.
The multi-pose furnace allows for installation in many different positions that are generally not available to more conventional units. Special care, however, must be given to various components of the furnace to insure that they operate effectively in each of the positions. One of these components is the inducer fan assembly. The motor is typically mounted in assembly upon isolators that effectively dampen motor vibration when the furnace is in an upright or upflow position. However, the isolators have been found to be sensitive to the furnace""s orientation and do not provide the same level of damping in all positions which can result in excessive noise and, in some extreme cases, may lead to early inducer fan failure.
It is a primary object of the present invention to improve the ability of a multi-poised furnace to operate efficiently in a variety of different positions.
It is a still further object of the subject invention to render the inducer fan assembly of a multi-poised furnace relatively insensitive to the furnace""s orientation.
Another object of the present invention is to provide a vibration isolation mount for an inducer fan motor that will reduce the unwanted effects of motor vibrations regardless of the motor""s orientation.
These and other objects of the present invention are attained by an inducer fan unit for use in a gas fired multi-poised furnace that includes an inducer housing. The housing has an opening in one of the housing walls and a cover is placed over the opening and is secured to the walls. The cover contains three brackets that are circumferentially spaced about its periphery at equal intervals. A support plate having the inducer motor attached to its front face is connected to the brackets by means of mounting tabs. Each mounting tab extends from the periphery of the support plate and has a mounting surface turned at about a 45xc2x0 angle with respect to the plane described by the front face of the plate with the plane of each support surface passing through the central axis of the plate. Each support face complements a mounting surface on one of the brackets and is secured thereto by a threaded fastener or the like. A vibration isolator is mounted between the two support surfaces. The reaction of the isolators is such that uniform damping is provided regardless of the furnace""s orientation.